ES2915899T3 - Contact device for a battery electric vehicle - Google Patents

Abstract

Contact device for a fast charging system for electrically powered vehicles, in particular electric buses or the like, the contact device comprising a contact unit support (24), the contact unit support having a contact unit (25 , 26), a charging contact of a charging contact device of the fast charging system being able to be contacted with the contact unit to form a pair of contacts, the contact device comprising a positioning device, the unit support being able to be positioned by means of the positioning equipment in relation to the charging contact device in such a way that an electrically conductive connection can be established between a vehicle and a stationary charging station, the positioning equipment having a pantograph or a rocker arm, by means of from which or from which the contact unit support can be positioned at least di vertical direction with respect to the charging contact device, the contact device being able to be arranged in the vehicle or in the charging station, the contact unit having a contact element (34), the contact unit having a contact element guide (39), the contact element in the contact element guide being movable in the direction of its longitudinal axis (44) with respect to the contact unit support, the contact unit having a connection line (36) for the connection to the vehicle characterized in that the connection line is fixed to the contact element.

Description

DESCRIPTION

Contact device for a battery electric vehicle

The invention relates to a contact device for a fast charging system for electric propulsion vehicles, in particular electric buses or the like, the contact device comprising a contact unit support, the contact unit support having a contact unit contact, a charging contact of a charging contact device of the fast charging system being able to be contacted with the contact unit to form a pair of contacts, the contact device comprising a positioning device, the contact unit holder being able to be positioned by means of the positioning equipment in relation to the charging contact device in such a way that an electrically conductive connection can be established between a vehicle and a stationary charging station, the positioning equipment having a pantograph or an oscillating link, by means of which or from which the contact unit support can be positioned at least vertically with respect to the charging contact device, the contact device being able to be arranged in the vehicle or in the charging station, the contact unit having a contact element, the contact unit having a contact element guide contact element, the contact element in the contact element guide being movable in the direction of its longitudinal axis relative to the contact unit carrier, the contact unit having a connection line for attachment to the vehicle.

Such contact units are already known from the state of the art and are regularly used as a module of a contact device for fast charging of electrically powered vehicles at a standstill or at a standstill. Electrically powered vehicles used in local transport, such as buses, can be continuously supplied with electrical energy, for example via a catenary. However, this presupposes the existence or maintenance of a catenary system. In order to be able to exploit the advantages of electric propulsion even without a catenary network, it is known to equip means of public transport with batteries or other types of energy stores. Continuous operation of the means of transport can be ensured in such a way that rapid charging of the batteries takes place when the means of transport is stopped at a standstill.

Various fast-charging systems are known from the state of the art for establishing an electrically conductive connection between a stationary charging station in the area of a stop and an electric vehicle or bus. For example, in an electric bus, a so-called current collector with a wiper can be arranged on a roof of an electric bus, a rail running longitudinally in the direction of travel being suspended above a roadway in the area of the stop. running of the electric bus. When the electric bus stops at the stop, the current collector is moved from the roof of the bus up to the rail, whereby an electrical bond is established for the duration of the planned stop of the electric bus at the stop, so that during this period a fast charge can be performed. However, two mutually independent current collectors and corresponding contact areas on the rail are necessary in order to form a charging circuit.

In addition, contact elements may be required, eg for a control line, grounding or data transmission. In this case, a number of contact elements are arranged in a contact device of a current collector or a fast charging system, which can be brought into contact with a corresponding number of charging contact elements arranged in the direction of travel of the electric bus and which can be formed, for example, by parallel rails. In this way, a greater number of contact pairings can be produced.

WO2015/01887A1 discloses a fast charging system in which a charging contact device in the form of a roof is contacted by a correspondingly embodied contact unit carrier of a contact device. The contact unit carrier is guided into a contact position by the fact that contact elements on the contact unit carrier can slide along the roof-like slopes of the load contact device in such a way that the contact unit support is centered on the charging contact device.

The contact elements are respectively part of a contact unit which is fixedly mounted on the contact unit carrier. Each contact unit comprises a contact element guide, within which the respective contact element is movable in the direction of its longitudinal axis relative to the contact unit carrier and is elastically mounted. This makes it possible to compensate for possible angular misalignment when bringing the contact unit support and load contact device together, or tilting of a bus at a stop as a result of a change in load or lowering of the bus, and always provide a safer contact. The respective contact units are connected to the vehicle via one or more connection lines. In particular, the connection lines are screwed to the contact element guide by means of cable lugs. Therefore, the current transmission takes place, for example, from an electrically conducting rail of the charging contact device to a contact element and from this through a gap that allows a movement of the contact element in the contact element guide, to the contact element guide to which the connecting line is clamped.

To establish safe current transmission from the contact element to the contact element guide, contact grease and a contact foil or lamellar ring are used. The disadvantage is that the contact unit support is exposed to environmental influences, such as snow or rain, as well as dirt and dust, which can penetrate the contact element or the gap in the contact element. despite the use of an annular seal. In special cases, this can lead to the contact element jamming or jamming in the contact element guide and thus no contact or indefinite contact sequence possible with the risk of formation of a electric arc. In order to prevent faults from occurring at low temperatures, provision can also be made to arrange a heating cartridge in the contact element guide. It is also known to silver the contact elements in order to favorably influence a contact resistance in the region of the contact element guide. If one contact unit fails, high currents will flow through the remaining contact units, which can cause excessive heating and failure of the entire fast-charging system. Therefore, contact units must be replaced or serviced at regular intervals to ensure safe contact.

Document EP1102360A1 discloses a waterproof structure for a contact device for an electrically powered motor vehicle.

Document EP1526626A2 relates to a charging system for a mobile robot.

Therefore, the present invention has the objective of providing a contact device as well as a fast charging system that allow an economical operation of the means of transport and a safe contact.

This task is achieved by a contact device with the features of claim 1 and a fast charging system with the features of claim 18.

In the contact device according to the invention for a fast charging system for electrically powered vehicles, in particular electric buses or the like, the contact device comprises a contact unit carrier, the contact device having a contact unit, which can be a charging contact of a charging device of the fast charging system being contacted with the contact unit to form a contact pairing, the contact device comprising a positioning device, the contact unit carrier being positionable by means of the positioning device positioning relative to the charging contact device in such a way that an electrically conductive connection can be formed between a vehicle and a stationary charging station, the positioning equipment having a pantograph or an oscillating link, by means of which or from which the contact unit support can be positioned in at least one direction vertical with respect to the charging contact device, the contact device being able to be arranged in the vehicle or in the charging station, the contact unit having a contact element, the contact unit having a contact element guide, being movable the contact element in the contact element guide in the direction of its longitudinal axis relative to the contact unit carrier, the contact unit having a connection line for attachment to the vehicle, the connection line being attached to the element contact.

The contact element, which is mounted on the contact element guide and is movable along its longitudinal axis, is therefore substantially directly attached to the connecting line, so that it is no longer necessary to use a gap between the guide of contact element and the contact element to transmit currents. Furthermore, then the connection line can move together with the contact element. A gap between the contact element and the contact element guide can also be dimensioned large enough to ensure that the contact element can always move. A lamellar ring, an annular seal and other components that negatively influence mobility can then also be dispensed with. Instead of a conductive grease or tribological synthetic material bearings, it is possible to use a corresponding grease or bearings, adapted for smooth operation of the contact element. Then it is no longer necessary to use heating cartridges or to take into account the heating of the contact unit as a result of a contact resistance by the gap. In this way, overall, the maintenance intervals for servicing and, if necessary, replacement of the contact unit can be significantly lengthened, whereby the transport means can be operated more economically. In addition, the probability of the contact element blocking is then also very low, so that the fast charging system can be operated more reliably.

According to the invention, the positioning equipment comprises a pantograph or an oscillating link, by means of which or by means of which the contact unit support can be positioned in at least vertical direction with respect to the load contact device, the device being able to be arranged contact in the vehicle or at the charging station. In the case of an oscillating link, a complementary coupling gear can be provided, which stabilizes the contact unit carrier relative to a load contact device or orients it in the corresponding direction. A pantograph or an oscillating link or a corresponding mechanical drive are particularly easy and inexpensive to manufacture. Additionally, the positioning device can also have a transverse guide, by means of which the contact unit carrier can be positioned. transversely with respect to the load contact device or to a direction of travel of the vehicle. The transverse guide can be arranged on a vehicle or on a pantograph or on an oscillating link of the positioning equipment. In both cases, the positioning device or a contact unit carrier arranged on the positioning device can be moved transversely to the direction of travel of the vehicle. By means of this shifting ability, it is possible, for example, to compensate for an incorrect positioning of the vehicle transversely to the direction of travel at a standstill. In addition, possible movement of the vehicle as a result of a unilateral lowering of the vehicle for loading and unloading of persons can be compensated in such a way that no displacement of the contact unit support with respect to the load contact device in the direction cross. The contact device can be arranged, for example, on the roof of the vehicle, so that the contact unit carrier can be moved from the vehicle roof to the charging contact device and back by means of the positioning equipment . Alternatively, the contact device may be arranged at the charging station, in which case the contact unit support can be moved from a support such as a mast or bridge to a standstill in the direction of a roof. vehicle with a charging contact device, and back.

Advantageously, the contact element can be made in the form of a pin. In this way, the contact element is particularly easy to manufacture and, for example, point contact can be made with a charging contact of a charging contact device. It is also advantageous if the bolt-shaped contact element is designed with rounded edges or completely rounded at its contact end. The contact element can then move along a load contact without causing major mechanical damage to the load contact or contact element. Alternatively, the contact element can also be made in another suitable shape.

Furthermore, the contact element can be made of copper and/or be unplated. Copper is particularly suitable for use for electrically conductive components, it being possible for the connection line to also be made of copper. Since there is no longer current transfer from a contact element surface to the contact element guide, silver plating of the contact element can be completely dispensed with, which considerably reduces the manufacturing costs of the contact element.

The contact element guide can then be designed as a guide sleeve surrounding the contact element. A guide sleeve can likewise be easily produced by turning, so that the contact element guide can also be realized more simply and economically. The guide bushing, which can also be self-lubricating, can have, for example, a thread with which the guide bushing can be screwed into the contact unit carrier and thus easily mounted. A comparatively large clearance fit can be made between the guide bushing and the contact element, since no current is dissipated through the guide bushing. In addition, provision can be made for the guide bush to have bearing bushes made of suitable materials. This means that the material of the guide sleeve can basically be chosen as desired. For example, the guide sleeve can then also consist of aluminium, a synthetic material or another dielectric material or have a dielectric material, in particular because excessive heating of the contact unit as a result of the contact resistance. One or more bearing shells can be made of a material with good sliding or sealing properties, for example PTFE.

Furthermore, provision can be made for a spring of the contact unit to cause a spring force on the contact element. An elastic bearing of the contact element can be realized by a simple compression spring, in particular a coil spring, within the contact element or the contact element guide. As a result, a point contact can be formed with a load contact under spring prestress. A spring force can be selected such that the contact element always moves out of the contact guide into a forward end position when the contact element is not in contact with a load contact.

The contact unit may comprise the connecting line and a connecting device, the connecting device being capable of connecting the contact element and the connecting line. Then, the joining device is made in such a way that the contact element is directly and immediately attached to the connection line through the joining device. In this way it can be ensured that the current is conducted from the contact element directly to the connection line and does not flow through other components of the contact unit. In particular, the connection device can be made in such a way that the connection line can be easily attached to the contact element.

The connecting set can have a connecting element, whereby the connecting element can form a ferrule which can be connected to one end of the connection line by plastic deformation. Then the connecting element can also be directly attached to the contact element by crimping, in which case the connecting line ends at the connecting element. In this way, the cable lugs known from the state of the art can be dispensed with. Unlike a cable lug, a comparatively higher current can be transmitted through the junction element. The ferrule can be embodied as a socket on the connecting element, the connecting line being able to be mounted particularly easily by inserting one end of the connecting line into the socket and crimping the socket by means of a crimping tool. the connecting line it can also be inseparably connected to the connecting element.

The connecting element and the contact element can each have threads, which are then screwed into one another. For example, if the connecting element is embodied in the form of a pin, a thread can be formed at one end of the connecting element, which can be easily screwed onto a thread of the screw-in contact element. In this way, it is also possible to easily separate the contact element from the connecting element with the connection line again, if the contact element has to be replaced, for example due to wear. To prevent undesired loosening of the screw connection, for example, a thread lock by geometric connection can be provided.

Furthermore, the connecting element and the contact element can respectively have cones which form contact surfaces which are in contact with one another. In this way, the connecting element and the contact element can also be connected to one another by means of a friction connection or come into contact with one another over a large area. Cones can also be used to secure a possible existing threaded joint. In particular, however, a comparatively large contact surface can be created, which ensures a connection with good electrical conductivity between the connecting element and the contact element. The connecting element can, for example, form a truncated cone at its end.

Furthermore, the connecting element can be glued to the contact element. An adhesive connection can be made particularly easily and can also be used to secure a screw connection. The adhesive connection, for example with an electrically conductive adhesive material, can also be made in the region of the contact surfaces of the connection element and the contact element. In this way, accidental detachment of the contact element from the connecting element can be prevented.

In another embodiment, the contact element can form the connecting element. The connecting element can then be formed on the contact element. In particular, the contact element can then be made in one piece together with the connecting element. In a particularly simple embodiment, the contact element can form a socket forming a ferrule at a connecting end opposite a contact end, into which the connecting line for connection to the contact element can be inserted.

A shoulder can be formed on the connecting element, which limits a movement of the contact element relative to the contact element guide. The bead can be, for example, an undercut diameter in the connecting element. The heel can be made for contact with the contact element guide in such a way that the contact element cannot accidentally fall out of the contact element guide. In this way, the butt can limit a front end position of the contact element.

The contact unit can have a closure cap that forms a heel stop. The closure cap can be designed as a contact element guide closure cap, which, if the contact element guide is configured as a guide sleeve, closes one end of the guide sleeve. A through hole can be made in the closing cover, through which the connection line, the contact element or a connecting element can pass. The bead can then come into contact with the closure cap, so that the stop is formed between the bead and the cap. The closure cap can also be screwed to the optionally present guide sleeve by means of a thread, so that the contact element can be easily removed from the guide sleeve by opening the closure cap.

It becomes possible to transmit especially high currents with the contact unit if the connection line has a conductor cross-section of at least 50 mm2, preferably 95 mm2. In the contact units known from the state of the art, several connection lines are threaded with a contact element guide through cable lugs. Since the use of cable lugs can be dispensed with by attaching the connecting line to the contact element, higher currents can also be transmitted via the connecting line, which is why a conductor cross-section as small as great. In this way, undesired heating of the connection conductor can be avoided.

The contact unit can be configured in such a way that a current of 500 A to 1,000 A, preferably 800 A, at a voltage of 750 V can be transmitted via the contact unit. 375 kW to 750 kW, preferably 600 kW, through the contact unit. Therefore, it may be sufficient to provide only one connecting line for attachment to the contact element. The vehicle can also be charged more quickly, as higher currents can be transmitted in less time. If necessary, the number of contact units in a contact unit carrier can also be reduced, whereby the contact device can be produced more economically.

The contact device can also have a plurality of contact units, for example for different phases, grounding or data transmission.

At least two contact elements can protrude at different heights with respect to a surface of the contact unit support. In this way, by performing at least two pairings between a contact element and a charging contact respectively, it is possible to guarantee a defined sequence when establishing the pairings of contacts. Then, when joining the contact unit support and the charging contact device, a sequence of contacts is compulsorily respected and always ensured due to the geometric arrangement of the contact elements in relation to the surface of the contact unit support. . In this way, accidental or faulty contacts or contact pairings can be easily avoided.

The contact unit carrier can have a housing formed by two parallel side walls made of a dielectric material, the side walls being able to be connected to one another by means of connecting bridges, the contact units being able to be arranged on the connecting bridges. The casing can be made, for example, of a synthetic material, and the parallel side walls can also be made of a fiber-reinforced synthetic material. In this way, the side walls can be manufactured in a particularly simple, stable and economical way. The housing can be made in such a way that the side walls are connected by means of the connecting bridges. The connecting bridges then define a relative distance between the side walls and, for example, can be screwed to the side walls. The connecting bridges can also be made of a synthetic material or also of a metal and be designed as a simple, rectangular strip. Through-holes can be formed within the connecting bridges, in which a contact unit is then inserted and fixed according to requirements. No special electrical insulation of the contact units or of the connecting bridges is necessary if the side walls are made of the dielectric material.

The fast charging system according to the invention has a charging contact device and a contact device according to the invention.

The charging contact device may form a receiving opening for the contact unit holder, the contact unit holder being insertable into the receiving opening of the charging contact device. The receiving opening may preferably be V-shaped. In the event of a relative deviation of the contact unit support when the contact unit support and the charging contact device are brought together towards the receiving opening, the V-shaped embodiment V of the receiving opening then causes a centering of the contact unit carrier. The receiving opening thus forms a guide for the contact unit holder, which can compensate for a deviation of a contact position in the charging contact device.

Advantageous embodiments of the fast charging system result from the dependent claims referring back to claim 1.

The invention can basically be used for any type of electric vehicle that is operated with batteries that need to be recharged.

In the following, preferred embodiments of the invention are explained in more detail with reference to the accompanying drawings.

They show:

Figure 1 : a contact unit support according to the state of the art in side elevation;

Figure 2: a contact unit in a perspective view;

figure 3: a partial sectional view of the contact unit of figure 2;

figure 4: a sectional view of a joining equipment of figure 3 ;

Figure 5: A perspective view of a contact unit support.

Figure 1 shows a contact unit support 10 as is known from the state of the art. The contact unit support 10 is an integral part of a contact device which is not shown in more detail here and is arranged in a contact device positioning equipment, so that the contact unit support 10 can move relative to the contact device. with a charging contact device also not shown here, and you can make contact with it. The contact unit carrier 10 is formed by a housing 11 with contact units 12, 13 and guide elements 14 for attachment to a transverse guide of the positioning equipment. The contact units 12 and 13 each have a contact element 15, contact element guides 16 or 17 and connection lines 18.

The connection lines are formed by conductors 19 with cable lugs 20, the cable lugs 20 being screwed to the contact element guide 16 or 17 to establish an electrical bonding contact. The contact elements 15 are movable in the direction of their longitudinal axis 21 in the contact element guide 16, protrude from a surface 22 of the housing 11 and are subjected to a spring force. To form a contact pair, one end of contact 23 is brought into contact with a charging contact of the charging contact device, during which contact element 15 is pressed slightly into the contact element guide. 16. There is then a current transmission from the contact of load to the contact element 15 and from this to the contact element guide 16 or 17 which in turn is attached to the connecting line 18. In particular, two connecting lines 18 are attached to the contact element guides 17 to be able to dissipate high currents through the connection lines 18.

A joint view of figures 2 to 5 shows a contact unit holder 24 with contact units 25, 26 in different views. The contact unit holder 24 also has guide elements 27 for fastening and guiding a contact device positioning device, which is not shown in more detail here, on a transverse guide. The contact unit support 24 has a casing 28 which is formed by two parallel side walls 29 of fiber-reinforced synthetic material. The side walls 29 are connected to each other by means of connecting bridges 30, 31, 32, the connecting bridges 30 and 31 respectively being provided with through-holes 33 to receive and fix the contact units 25 or 26. The contact elements 34 of the contact units 25, 26 protrude from a surface 35 of the housing 28 in such a way that the contact elements 34 can come into electrical contact with the charging contacts, not shown here, of a charging contact device.

The contact unit 25 shown in FIGS. 2 to 4 consists of a connection line 36 with an insulated conductor 37 and a cable lug 38 for electrically conductive connection of the contact unit 25 to a vehicle, as well as the element contact element 34 and a contact element guide 39. The contact element guide 39 consists of a guide sleeve 40 with bearing bushes 41 and 42 as well as a closing cap 42 and a spring 43. The contact element 35 is movable in the direction of its longitudinal axis 44 within the guide bushing 40. A contact end 45 of the contact element 34 is made completely rounded. A connecting end 46 of the contact element 34 has a cavity 47 in which the spring 34 is inserted. The closing cap 42 is screwed onto the guide bushing 40, so that the guide bushing is closed and the spring 43 is disposed. between the closure cap 42 and the connecting end 46, the spring 43 being able to exert a spring force on the contact element 34. In addition, on an outer surface 48 of the guide bushing 40 a thread 49 is made, by means of the which the guide bushing 40 is screwed into the through hole 33 and is thus fixed to the connecting bridge 31. A collar 50 on the guide bushing 40 serves to define an installation position of the guide bushing 40.

Furthermore, the contact unit 25 comprises a joint element 51 which is screwed into the contact element 34. Therefore, the joint element 51 has a thread 52, a cone 53 and a ferrule 54 which is attached to the conductor 37 forming a crimp joint 55 with one end 56 of conductor 37. Ferrule 54 is formed by a hole 57 in joint 51. End 56 is stripped and inserted into hole 57 and clamped with ferrule 54 with a crimping tool not shown here. A heat shrink hose 59 covers an insulation 58 and the crimp joint 55.

In addition, a shoulder 60 is made on the connecting element 51, which forms a stop 61 with the closing cover 42, thus limiting a position of the contact element 34 with respect to the surface 35. The connecting element 51 passes through a through hole. 62 in the closing cap 42 and is screwed, with the thread 52, into the contact element 34. The cone 53 forms a contact surface 63 with an inner cone 64 of the contact element 34. In order to prevent the connecting element from 51 is released from the contact element 34, it may be secured by an adhesive material. In particular, through the realization of the crimp connection 55 and through the contact surface 63 and the thread 52, the transmission of comparatively high currents from the contact element 34 to the conductor 37 is made possible without a break in contact being possible. as known from the state of the art. At the same time, the contact element 34 can be prevented from jamming in the contact element guide 39, since a proper clearance fit can be made between the contact element 34 and the guide bushing 40 which then no longer has any clearance. used to transmit currents. In addition, silvering of the contact element can also be dispensed with. Furthermore, the number of connection lines 36 can be reduced, since the connection lines 36 can now be used with a comparatively larger cross section.

Claims (19)

1. Contact device for a fast charging system for electrically powered vehicles, in particular electric buses or the like, the contact device comprising a contact unit support (24), the contact unit support having a contact unit (25, 26), a charging contact of a charging contact device of the fast charging system being able to be contacted with the contact unit to form a pair of contacts, the contact device comprising a positioning device, the support being able to be positioned of contact unit by means of the positioning device in relation to the charging contact device in such a way that an electrically conductive connection can be established between a vehicle and a stationary charging station, the positioning device having a pantograph or an oscillating link, by means of which or of which the contact unit support can be positioned at least in vertical direction with respect to the charging contact device, the contact device being able to be arranged in the vehicle or in the charging station, the contact unit having a contact element (34), the contact unit having a contact element guide (39), the contact element in the contact element guide being movable in the direction of its longitudinal axis (44) relative to the contact unit carrier, the contact unit having a connection line (36) for attachment to vehicle characterized because the connecting line is fixed to the contact element. 2. Contact device according to claim 1, characterized because the contact element (34) is made in the form of a bolt. 3. Contact device according to claim 1 or 2, characterized because the contact element (34) is made of copper and/or is not silver-plated. Contact device according to one of the preceding claims, characterized in that the contact element guide (39) is embodied as a guide bushing (40) surrounding the contact element (34). Contact device according to one of the preceding claims, characterized in that a spring (43) of the contact unit (25, 26) causes a spring force on the contact element (34). Contact device according to one of the preceding claims, characterized in that the contact unit (25, 26) comprises the connecting line (36) and a connecting unit, the connecting unit connecting the contact element (34) and the connecting line. Contact device according to one of the preceding claims, characterized in that The joint set has a joint element (51), the joint element forming a ferrule (54) which is attached to one end (56) of the connecting line (36) by plastic deformation. 8. Contact device according to claim 7, characterized in that the connecting element (51) and the contact element (34) respectively have threads (52) which are screwed together. 9. Contact device according to claim 7 or 8, characterized in that the connecting element (51) and the contact element (34) respectively have cones (53, 64) which form contact surfaces (63) which are in contact with each other. 10. Contact device according to any one of claims 7 to 9, characterized in that the connecting element (51) is glued to the contact element (34). 11. Contact device according to claim 7, characterized in that the contact element forms the connecting element. 12. Contact device according to any one of claims 7 to 11, characterized in that A shoulder (60) is formed on the connecting element (51) which limits a movement of the contact element (34) relative to the contact element guide (39). 13. Contact device according to claim 12, characterized because the contact unit (25, 26) has a closure cap (42) which forms a stop (61) for the heel (60). Contact device according to one of the preceding claims, characterized because the connection line (36) has a conductor cross-section of at least 50 mm2, preferably 95 mm2. Contact device according to one of the preceding claims, characterized because the contact unit (25, 26) is designed in such a way that a current of 500 A to 1000 A, preferably 800 A, can be transmitted through the contact unit at a voltage of 750 V. 16. Contact device according to one of the preceding claims, characterized because at least two contact elements (34) protrude at different heights with respect to a surface (35) of the contact unit support (24). Contact device according to one of the preceding claims, characterized because the contact unit support (24) comprises a casing (28) formed by two parallel side walls (29) of a dielectric material, the side walls being joined together by means of connecting bridges (30, 31, 32), the contact units (25, 26) being arranged on the connecting bridges. 18. Fast charging system with a charging contact device and a contact device according to one of claims 1 to 17. 19. Fast charging system according to claim 18, characterized because the charging contact device forms a receiving opening for the contact unit holder (24), the contact unit holder being insertable into the receiving opening of the charging contact device.